Fuel injection pump



Dec. 6, 1938. E. c. GAMBRELL 2,138,349

FUEL INJECTION PUMP Filed June 3, 1936 2 Sheets-Sheet 1 Fig.1

4.7 Ernest C. Gambrei] INVENTOR.

M ATT NEY.

Dec. 1938. E. c. GAMBRELL FUEL INJECTION PUMP Filed June 5, 1956 2 Sheets-Sheet 2 1 I w n m T. N B w E vm .T nr m 4 0 $9 a D r. W E

Patented Dec. 6, 1938 UNITED STATES PATENT OFFICE I FUEL mmcrron PUMP Ernest O. Gambrell, Wichita Falls, Tex. Application it... s, 1936, Serial No. 83,249

g Claims. (01. nag-139) This invention relates to means for efl'ecting an airless injection of liquid fuel into'the combustion chamber of internal combustion engines, especially engines operating on the Diesel or 5 similar principle.

In engines of this type, wherein combustion is had when liquid fuel is injected into the combustion chamber when said chamber contains air that has been so highly compressed as to generate heat sufiieient for such fuel combustion, it is necessary and desirable that provision be made to alter certain individual combustion factors, subject to individual control, to insure eflicient operation of the engine operating at varying speeds and under varying loads.

First, provision must be made for varying the quantity of fuel injectw into the combustion chamber per engine cycle, according to load and speed requirements. Second, provision must be made for varying the time of injection of fuel into the combustion chamber to insure efllcient operation over a wide range of engine loads and speeds. Third, provision must be made for varying the injection pressure, which pressure determines the velocity of the fuel supplied to the combustion chamber, to insure proper fuel injection and proper fuel combustion during all the various engine conditions from starting to full speed and from no-load to full-load.

Pumps in common use at this time depend upon some auxiliary means to provide certain of these adjustments.

It is the object of this invention to provide a pump which is sturdy inconstruction yet simple and compact, whereby the quantity of fuel injected, the time of such injection and the pressure of such injection may be instantly controllable, either. separately or in unison, said variations of quantity, time and pressure being effected by adjustments within the pump mechanism and without the use of auxiliary means of control. p

A further object of this invention is to provide a pump of the actuating piston type, the

actuation of which may be had by the use oi? any suitable means for effecting a reciprocating motion and not limited to the use of special shaped cam or any other specific means.

A further object of the invention is to provide a pump whereby the fuel to be injected is accumulated in the pump in measured quantity and the energy required to make such injection is generated and stored Within the pump prior to the time for delivery to the engine and providing means for releasing said energy to eil'ect injection at the proper time, thus making it unnecessary to use a spring-loaded nozzle or any other obstruction to the free flow of the fluid from the pump to the combustion chamber of the engine, but rather injection may be made 5 Y through an open type nozzle.

A still further object of the invention is to provide a pump by which fuel is injected into the combustion chamber of the engine by the joint action or two pressure members, one of 10 which is operated in accordance with the engine speed while the other is independent of such speed.

Another object of the invention is to provide a pump mechanism whereby the injection pressure 15 will automatically vary within certain limits, in proportion to engine speed, i. e., increased injection pressure will result from increased engine speed.

And a still further object of the invention is 20 to provide a pump mechanism embodying the above advantages and having the further advantage that it does not employ any check valves in its operation.

One form of construction embodying this in- 25 vention is shown in the accompanying drawings, wherein:

Figure 1 is a central longitudinal sectional view on the line l--l of Figure '7.

Figure 2 is a perspective view of the plunger. 30

Figure 3 is a perspective view of the piston.

Figure 4 is a detail sectional view on the line 4'4 of Figure 1.

Figure 5 is a detail section on the line 5-5 of Figure l. 35

Figure 6 is a detail cross section on the line 6-6 of Figure 1.

Figure 7 is a detail section on the line '|-l of Figure 1.

Figure 8 is a cross sectional detail on the line 40 8-8 of Figure 1.

Corresponding and like parts are referred to in the following description and designated in the several views of the drawings by life reference characters. 45

The pump is compact and comprises in a single organized structure all the essential parts to effeet the desired results under varying conditions of load and speed. These parts are enclosed in a suitable housing of such construction as to admit 50 of ready access thereto for assembling, inspection and removal for replacement or other purposes. The 'working parts include a cylinder, a piston therein, a plunger within the piston movable therewith and independently thereof, con- 55 trol means hereinafter more particularly described and operating mechanism for imparting a reciprocatory motion to the piston. The piston comprises alined sections connected for unitary rectilinear movement but independently rotatable to effect desired adjustments as occasion may require.

The details and manner of operation will be more fully described hereinafter and, upon reference to the drawings hereto attached, the housing is designated by the numeral I4, which housing has an inspection plate 36 removably attached to a side thereof for gaining access thereto for assembly and inspection of the parts. An upper cylinder I and a lower cylinder 5| are fitted in partitional portions of the housing I4, being locked in place by rings 40 and 40a respectively, and receive the piston. The cylinder I5 is closed at its upper end by a cap 30 and has formed in a side thereof lateral openings 3|, 34 and 39, the opening 3| functioning as a vent and the openings 34 and 39 providing for the flow of liquid between pressure chamber I2 and storage chamber 35 respectively within and exterior to the cylinder I5. A valve 33 within the upper portion of the cylinder normally closes the opening 34 and is held seated by a spring 32. A bonnet 29, secured to the housing and forming a part thereof, encloses the upper portion of the cylinder I5 and forms the storage or fluid containing chamber 35. The cylinder 5| is formed with a fuel inlet 25 and a fuel outlet 53. The inlet 25 communicates with a chamber 23 which receives a nipple 24 screwed into a side of the housing I4.

The piston is fitted in the cylinders I5 and 5| and comprises alined sections I3, 55 and 62 which are connected in any preferred way, as by collars l8 and 41 and separated by threaded locking rings I9, to have a unitary rectilinear movement but said sections are free to have an independent rotary movement for various adjustments, as will appear from the following description. The sectional piston is hollow to receive the plunger which is operable therein. A portion of the upper edge of the piston is cut away to provide a helical edge 38 which coacts with the opening or port 39 to provide a variable passage between the chambers I2 and 35 for the flow of a fluid therebetween. An annular passage 50, axial opening 52 and lateral openings 26 and 54 are formed in the lower portion of the piston, the opening 26 connecting the inlet 25 with the opening 52 and the opening 54, which is oblique, coacting with the outlet 53. Rings 60a, 69b and 660 are confined longitudinally between the cylinders I5 and 5|, being interconnected therewith and with each other at 44, and obtain a close fit with the respective sections I3, 62 and 55 of the piston which are mounted therein. A pin and groove connection I6-I'l connects each of the rings with the coacting piston section to admit of a reciprocatory movement of the piston as a unit, and an independent rotary adjustment of the piston sections upon turning the individual controlling rings 60a, 60b and 600, as will be readily appreciated. The rings may be rotated in any predetermined manner as by cog teeth 45 and racks. 46a, 46b and 460, slidably mounted in the housing I4.

The plunger is mounted in the piston and comprises a head 37, a body formed with a longitudinal slot 29 and a reduced end portion 22 having a close fit in the axial opening 52. head 31' fits snugly within a chamber 43 formed in the piston section I3. A pin 2| carried by the piston section 62 passes transversely through the slot 20 and effects rotary adjustment of the plunger when the ring 60b is turned. The lower end of the plunger is cut away to provide a helical edge 49 which coacts with the opening 26 to provide a variable fuel inlet. A helical spring 48 mounted on the reduced end of the plunger normally exerts an upward pressure thereon. This spring is disposed within an enlarged portion of the piston opening. The piston sections l3 and 55 and plunger head 31 have oil grooves 4| and 42 respectively therein to facilitate operation. The means for reciprocating the piston consist of an eccentric 58 on a shaft 64 mounted in the housing I4, and a hollow head formed of sections 5'! and 51a secured together by screws 21 extending through spacers 28, the section 51 being connected to the lower end of the piston by a loose swivel formed of sections 56 and 6| to reciprocate the piston without placing side thrust thereon. The shaft 64 is journaled in bearings 65, shown in Fig. 7, and has a gear 63 keyed thereto and adapted to be driven by or in timed relation with the engine crankshaft. Obviously, any preferred means may beresorted to for effecting a similar result.

In operation, fluid, such as oil, is supplied to the chamber or fluid space 35 through the opening in the bonnet or cover 29 which is shown to be closed by the plug I I. Engine fuel is delivered at low pressure to the fuel inlet chamber 23 through suitable connection such as the nipple 24, and passes through passage 25 to annular groove 50.

In the drawings, Figure 1 shows the pump to be in the bottom dead center position, i. e., injection has been completed and the eccentric 58 has drawn the piston downward to its lowest point of travel and the pump is now in position to be reloaded for the next injection. The piston on its downward stroke has created a partial vacuum in chamber I2 of cylinder I5 and near the bottom of the stroke it has uncovered passage 39, drawing fluid into chamber I2 from surrounding or communicating fiuid space 35. Likewise, since no pressure exists in the chamber I2 against the head 31 of the accumulation and injection plunger, during the downward stroke of the piston, the plunger travels upward under the urge of plunger return spring 48, thus creating a partial vacuum in accumulation chamber 52 until the plunger uncovers passage 26, at which time fuel enters through passage 26 to fill the chamber 52. Now it will be seen that as the piston starts upward the passage 39 is closed off and the fluid entrapped in chamber I2 of cylinder I5 is subjected to pressure, which pressure acts upon the head 31 of the plunger, tending to force it downward and in doing so the plunger closes inlet passage 26 and traps a quantity of fuel in the accumulation chamber 52. From this point, the upward travel of the piston creates an increasingly greater pressure in chamber I2 against the head of the plunger and consequently a greater pressure upon the entrapped fuel in the accumulation chamber 52. Near the uppermost point of travel of the piston, the oblique groove 54 is brought into registry with the outlet passage 53, at which time the pressure that has been built up tending to force the plunger downward is exhausted in ejecting the fuel from the accumulation chamber 52 through the outlet passage 53 and subsequently to the combustion chamber of the engine. The piston then returns downward to make ready for another injection.

Since the pressure in chamber I2 upon the head 31 of the plunger will transmit a like pressure upon the fuel that is trapped in accumulation chamber 52, it will be seen that bymaking the head 31 of the plunger larger than the part 22 which acts in chamber 52, a greater per square inch pressure may be had in the accumulation chamber 52 than exists in chamber l2. For example, assume that the area of the piston head is one square inch and that the pressure existing in the chamber i2 and acting upon said head is one hundred pounds per square inch, a pressure of one hundred pounds will be exerted downward upon the plunger. Assume that the area of the plunger which engages in the accumula: tion chamber to be one fourth of one square inch, and it will be seen that the one hundred pounds pressure is existent over an area of one fourth of one square inch and the pressure in the accumulation chamber will be equal to four hundredpounds per square inch.

. The sliding member or valve 33 which is urged downward by spring 32 serves to act as a pressure reducing means. So long as the pressure in chamber l2 does not exceed the strength of the spring 32, the passage. 34 remains covered and no fluid can escape from the chamber l2. However, when theexisting pressure ,does exceed the strength of the spring 32, the member 33 is caused,

to slide upward, uncovering passage 34 and allowing a part of the trapped fluid to escape from the chamber reducing the pressure therein. It will be seen that this passage is restricted in size and .if the pump is operating with a pressure that will uncover this port on each stroke, only a limited amount of the fluid will be able to pass out of the chamber through this passage and it will be seen that the faster the speed the less time that is allowed on each stroke forany of the fluid to pass out and, consequently, the greater the existing pressure at the time of injection. This will afford an automatic increase in pressure as the speed of the engine is increased, which is desirable. The rack 46a may be set to give the desired pressure, depending upon the weight of the fuel used, and while this adjustment may be readily changed at anytime, changes in this adjustment should not be necessary after it is once set unless a different weight of fuel is used, although it may be changed to give an increased pressure at the time of startingthe engine or at any. other time to meet any requirements for increased pressure.

It has been shown that by rotating the piston section i3, which changes the position of helical edge 38 with respect to inlet passage 39 and thereby trapping a greater or lesser amount of fluid in the chamber I2, the injection pressure may be varied.

Also, it has been shown that by rotation of section 62 of the piston, which, .in turn, causes the accumulation and injection plunger to be rotated, changing the position of the helical edge 49 with respect to the inlet passage 26 and thereby trapping a greater or lesser amount of fuel in the accumulation chamber 52, the ,amount of jection. will depend upon the velocity with which it is forced out and, consequently, will be dependent upon the injection pressure.

Further, I have attempted to show that an automatic increase in the injection pressure, de-

\ pending upon the engine speed, is had without changing the adjustment of rack 46a, this being accomplished by use of the sliding member or valve 33 and the restricted outlet passage 34, a described. l

Having thus'described the invention, what I claim is:

1. A fuel injection pump for internal combustion engines comprising a cylinder having a fuel inlet and a fuel outlet, a piston in the cylinder having a fuel accumulation chamber adapted to the other opening and operable by the pressure built up by the advance of the piston to effect areaction on the plunger to move it against the action of the spring associated therewith.

2. A fuel injection pump for internal combustion engines comprising a cylinder having a fuel inlet and a fuel outlet, and having a pressure accumulation chamber anda fluid containing chamher, there being openings connecting the two chambers, a piston and plunger operating in the cylinder to control the outlet and the inlet respectively, and the piston having an inclined portion coacting with one of the openings between the pressure accumulation and fluid containing chambers to vary the effective size of said opening, and a spring actuated member for closing the other opening and operable by the pressure built up by the advance of the piston to effect a reaction on the plunger to move it against the action of the spring associated therewith.

3. A fuel injection pump for internal combustion engines comprisinga cylinder having a fuel inlet and a fuel outlet, apiston operatively mounted in the cylinder and having a fuel accumulation chamber therein, said piston having an oblique opening in position for connecting the fuel accumulation chamber with the fuel outlet to vary the time of opening of the fuel outlet upon turning of the piston relative to the cylinder, a plunger operatively mounted in the fuel accumulation chamber and having an inclined portion in position to coact with and vary the time of out off of the inlet to the fuel accumulation chamber upon.-

turning movement of the plunger, the pump having a pressure accumulation chamber in communication with the piston and plunger and having a fluid containing chamber with openings connecting said chambers, the piston having an inclined portion in position to coact with one'of said openings, and a spring actuated member in position for controlling the other opening and operable relative to said opening by the fluid pressure in the pressure accumulation chamber.

4. In a fuel injection pump for internal combustion engines, the combination of a cylinder, and a piston therein having longitudinally aligned sections connected for unitary rectilinear move ment and independent turning adjustment.

5. In a fuel injection pump for internal combustion engines, the combination of a cylinder, 9. piston therein having longitudinally aligned sections connected for unitary rectilinear movement and independent turning adjustment, and means operatively connected with the respective sections for independent adjustment thereof.

6. A fuel injection pump for i ,ternal combus tion engines comprising a cylind r having a fuel inlet and a fuel outlet, and a piston therein embodying longitudinally alined sections connected for unitary rectilinear movement and independent rotary adjustment.

7. A fuel injection pump for internal combustion engines comprising a cylinder having a fuel inlet and a fuel outlet, a sectional piston therein, and independent means for selectively turning the respective piston sections.

8. A fuel injection pump for internal combustion engines comprising a cylinder having a fuel inlet and a fuel outlet, a sectional piston therein, a rotatable member associated with each piston section to turn therewith, and means for selectively turning the members to adjust the piston sections.

9. A fuel injection pump for internal combustion engines comprising a cylinder having a fuel inlet and a fuel outlet, a sectional piston therein, a ring on each piston section having a pin and groove connection therewith to prevent independent turning, and means for selectively rotating the several rings.

10. A fuel injection pump for internal combustion engines comprising a cylinder having a fuel inlet and a fuel outlet, and embodying spaced members in longitudinal alinement, a sectional piston in the cylinder for controlling the flow of fuel therethrough, rings on the piston each having a pin and groove connection with one of the sections to prevent independent turning thereof, said ringsbeing confinedbetween the spaced members of the cylinder, and means associated with the rings for turning thereof to rotatably adjust the piston sections.

11. A fuel injection pump for internal combustion engines comprising a cylinder having a fuel inlet and a fuel outlet, a sectional piston therein, a plunger in the piston having connection with a section thereof to turn therewith, and independent means for turning the respective piston sections to rotatably adjust said sections and the plunger.

12. A fuel injection pump for internal combustion engines comprising a cylinder having a fuel inlet and a fuel outlet and having a pressure accumulation chamber and a surrounding fluid containing chamber, there being openings connecting the two chambers, a sectional piston in the cylinder having a portion cut away to provide an inclined edge to coact with one of the openings connecting the pressure accumulation and surrounding fluid containing chambers, and having a fuel accumulation chamberterminating in an oblique discharge to coact with the cylinder fuel outlet, and a plunger in the piston having an inclined portion to coact with the fuel inlet of the cylinder and piston.

13. A fuel injection pump for internal combustion engines comprising longitudinally alined spaced cylinders, one of the cylinders having a fuel inlet and a fuel outlet and another one of the cylinders being provided with a pressure accumulation chamber and a connecting fluid storage chamber, a sectional piston in the cylinders having oblique cut away portions one of which coacts with the fuel outlet and the other with the passage between the pressure accumulation and storage chambers, a control member as sociated with each section of the piston to turn therewith without interfering with the reciprocation of the piston as a unit, means for selectively turning the control members, a plunger in the piston having an inclined cut away portion to coact with the fuel inlet and having connection with one of the control members to turn therewith, and a spring actuated member in the pressure accumulation chamber to control the flow of fluid between said chamber and the storage chamber.

14. A fuel injection pump for internal combustion engines comprising a cylinder having a fuel inlet and a fuel outlet, a piston in the cylinder, 9. fuel accumulation chamber adapted to register with the said inlet and outlet, a plunger within the piston adapted to control the closing of the fuel inlet to the fuel accumulation chamber, a spring normally holding the plunger in open position, the cylinder having a pressure accumulation chamber in which both the piston and plunger operate, the pump having a fluid containing chamber, and the cylinder being provided in a side with openings to establish communication between the pressure accumulation and the fluid containing chambers, one of the said openings being controllable by the piston and another of said openings being restricted to control the outflow of fluid from the pressure accumulation chamber. 15. A fuel injection pump for an internal com bustion engine comprising a structure having a fuel accumulation passage therein, means for trapping a predetermined variable charge of fuel in said passage, hydraulic means including a piston for applying pressure to said trapped charge of fuel in the passage, said structure having an outlet adapted to receive the discharge of said charge of fuel, and means for adjusting said piston for varying the pressure of the hydraulic means applied to the trapped charge of fuel in the passage.

16. A fuel injection pump for! an internal combustion engine comprising a structure having a fuel accumulation passage therein, means for trapping a predetermined charge of fuel in said passage, positively operated means for applying pressure to said trapped charge of fuel in the passage, said structure having an outlet, and control means adjustable independently of the pressure applying means for varying the time of discharge relative to the operation of the pump.

17. In a fuel injection pump for an internal combustion engine, the combination of a structure having a fuel accumulation passage therein and having a fuel outlet, means for trapping a predetermined charge of fuel in said passage, a positively operated piston for applying pressure to said trapped charge of fuel in the passage and having means for controlling the time of discharge of fuel from the passage to the outlet relative to the operation of the pump upon relative bodily movement of the piston and structure.

piston for controlling the time of discharge of fuel from the passage to the outlet relative to the operation of the pump upon relative bodily adjustment of the piston and structure, and means for causing relative bodily movement between the piston and structure to vary the time of said discharge of fuel from the passage.

19. In a fuel injection pump for an internal combustion engine, the combination of a struc-' ture having a fuel accumulation passage therein and having a fuel outlet, means for trapping a charge of fuel in said passage, a positively operated piston for applying pressure to said trapped charge of fuel in the passage, said piston having a passageway in position for discharge of fuel from the accumulation passage to the outlet, and means for causing relative adjustment between the piston and structure, said passageway and outlet being so constructed and arranged as to vary the time of the discharge of fuel relative to the operation of the pump upon said relative adjustment between the piston and structure.

20. In a fuel injection pump for an internal combustion engine, the combination of a structure having a fuel accumulation passage therein and having a fuel outlet, means for trapping a charge of fuel in said passage, a piston separate from said fuel trapping means for applying pressure to said trapped charge of fuel in the passage,

said piston having a spiral passageway in position for discharge of fuel from the accumulation.

passage to the outlet to vary the point of the passageway registering with the outlet upon relative adjustment between the piston and structure.

21. In a fuel injection pump for an internal combustion engine, the combination of a structure having a fuel accumulation passage therein and having a fuel outlet, means for trapping a charge of fuel in said passage, a piston separate from said fuel trapping means for applying pressure to said trapped charge of fuel in the passage, said piston having a spiral passageway in position for discharge of fuel from the accumulation passage to the outlet to vary the point of the passageway registering with the outlet upon relative adjustment between the piston and structure, and means for causing relative adjustment between the piston and structure.

22. In a fuel injection pump for an internal combustion engine, the combination of a structure having a fuel accumulation passage therein and having a fuel outlet, means for trapping a charge of fuel in said passage, a piston separate from said fuel trapping means for applying pressure to said trapped charge of fuel in the passage, said piston having a spiral passageway in position for discharge of fuel from the accumulation passage to the outlet, and means for causing relative adjustment between said piston and structure to bring different portions of the spiral passageway into position for registry with the outlet.

23. In a fuel injection pump for an internal combustion engine, the combination of a structure having a fuel accumulation passage therein for a charge of fuel and having a fuel outlet, positively operated means for applying pressure to said charge of fuel in the passage, and means forming a spiral passageway in position for discharge of fuel from the accumulation passage to the outlet and adjustable relative to said outlet and relative to the pressure applying means to vary the point of the spiral passageway registering with the outlet.

24. In a fuel injection pump for .an internal combustion engine, the combination of a structure having a fuel accumulation passage therein for a charge of fuel and having a fuel outlet, positively operated means for applying pressure to said charge of fuel in the passage, and means forming a spiral passageway in position for discharge of fuel from the accumulation passage to the, outlet, and means for adjusting said passageway means relative to the structure and relative to the pressure applying means to vary the point of the spiral passageway registering with the outlet.

25. In a fuel injection. pump for an internal.

combustion engine, the combination of a cylinder structure, a piston operatively mounted in said cylinder structure and having a fuel accumulation passage therein and having an inlet and outlet therefor, a plunger mounted in said passage and having an approximately spiral portion in position to control the inlet, and hydraulic means for actuating said plunger lengthwise with re spect to the piston.

26. In a fuel injection pump for an internal combustion engine, the combination of a cylinder structure, a piston operatively mounted in said cylinder structure and having a fuel accumulation passage therein provided with an inlet and outlet, means for operating said piston, a plunger mounted in said passage and having an approximately spiral portion in position to control the inlet and hydraulic means including portions of the piston and plunger for actuating said plunger lengthwise relative to the piston.

27. In a fuel injection pump for an internal combustion engine, the combination of a cylinder structure having a fluid pressure chamber therein,

a piston operatively mounted in said cylinder chamber and having an approximately spiral portion in position to control the inlet.

28. In a fuel injection pump for an internal combustion engine, the combination of a cylinder structure having a fluid pressure chamber therein, a piston operatively mounted in said cylinder structure for applying pressure to the fluid in the pressure chamber, said piston having a fuel accumulation passage therein provided with an inlet and outlet, means for operating said piston, a plunger in the fuel accumulation passage and responsive to the pressure in the pressure chamber and having an approximately spiral portion in position to control the inlet, and means for turning said plunger to adjust said spiral portion relative to the inlet.

29. In a fuel injection pump for an internal combustion engine, the combination of a cylinder structure having a fluid pressure chamber therein, a piston operatively mounted in said cylinder structure for applying pressure to the fluid in the pressure chamber, said piston having a fuel accumulation passage therein provided with an inlet and outlet, means for operating said piston, a plunger in the fuel accumulation passage and responsive to the pressure in the pressure chamber and having an approximately spiral portion in position to control the inlet, resilient means acting on said plunger against the fluid pressure in the pressure chamber, and means for turning said plunger to adjust said spiral portion relative to the inlet.

30. Inafuel injection pumpfor an internal com- I means for said pressure accumulation chamber;

31. A fuel injection pump for internal combus-,

tion engines comprising a cylinder, a structure having a fuel accumulation chamber therein, a piston operable in the cylinder, means rotatable relative to the structure for varying the quantity of fuel discharged from thefuel accumulation chamber, means forming a pressure accumulation chamber in which said piston operates, said structure having a fuel outlet passage for the fuel accumulation chamber, means for varying the time of beginning of the fuel discharge to the outlet passage, and means for reciprocating said piston.

32. A fuel injection pump for an internal combustion engine comprising a structure having a fuel accumulation passage therein, a plunger operatively mounted in said passage to trap a charge of fuel in said passage, hydraulic means including a piston and acting on said plunger for applying pressure tosaid trapped charge of fuel in the passage, said structure having an outlet adapted to receive the discharge of said charge of fuel, and means for adjusting said piston for varying the pressure of the hydraulic means applied to the trapped charge of fuel in the passage.

33. A fuel injection pump for an internal combustion engine comprising a structure having a fuel accumulation passage therein, a plunger operatively mounted in said passage for trapping a predetermined charge of fuel therein, hydraulic means including a fluid chamber and piston structure for applying pressureto said plunger acting on the trapped charge of fuel in the passage, said structure having an outlet adapted to receive the discharge of said charge of fuel, and means for adjusting said piston structure for varying the pressure of the hydraulic means applied to the trapped charge of fuel in the passage.

34. A fuel injection pump for an internal combustion engine comprising a structure having a fuel accumulation passage therein and having a hydraulic chamber, a plunger operatively mounted in said fuel accumulation passage and having one end portion in position for trapping a predetermined charge of fuel therein and the other end portion in operative communication with the hydraulic chamber, a piston member operative in the hydraulic chamber for applying pressure to the plunger acting on the trapped charge of fuel in the passage, means for adjusting said piston for varying the pressure of the hydraulic chamber applied to the plunger, said structure having an outlet adapted to receive the discharge of said charge of fuel, and means for varying the time of the opening of the discharge outlet relative to the operation of the engine.

35. In a fuel injection pump for an internal combustion engine, the combination of a structure having a fuel accumulation passage therein and having an inlet and outlet for said passage, a plunger operatively mounted in said passage and having an inclined portion in position to control the inlet, hydraulic means including a piston and for actuating said plunger lengthwise relative to the structure, and means for adjusting said piston for varying the pressure of the hydraulic means applied to said plunger.

ERNEST C. GAMBRELL. 

